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um campo: ID, nome, salário e nome.

A aplicação CRUD (criar, ler, atualizar e excluir) é a mais importante aplicação para criar qualquer projeto. Ela oferece ideias para desenvolver grandes projetos. No SpringMVC, podemos desenvolver uma aplicação CRUD simples.

在这里,我们使用 Aqui, usamos JdbcTemplate

interagir com o banco de dados.

criar uma tabela99Aqui, usamos o emp existente no banco de dados MySQL4tabela. Ela possui


um campo: ID, nome, salário e nome.

1Exemplo CRUD do Spring MVC

、Adicionar dependências ao arquivo pom.xml.

 .0.-- <!//https:/mvnrepository.com/artifact/spring-pom.xml -->
jdbc
    <dependency>/<groupId>org.springframework
    <groupId>org.springframework-webmvc/<artifactId>jdbc
    <version>5.1.1.RELEASE</version>
</dependency>
.0.-- <!//https:/mvnrepository.com/webmvc/org.apache.tomcat-tomcat -->
jdbc
    jasper/<groupId>org.springframework
    <groupId>org.apache.tomcat-<artifactId>tomcat/<artifactId>jdbc
    <version>9java<12</version>
</dependency>
    .0.-- <!//https:/mvnrepository.com/alpha/alpha-jasper -->
jdbc  
    javax.servlet/<groupId>org.springframework  
    api-<artifactId>servlet/<artifactId>jdbc  
    <version>3api-.0-1</version>  
</dependency>
.0.-- <!//https:/mvnrepository.com/alpha/jstl -->
jdbc
    javax.servlet/<groupId>org.springframework
    <groupId>javax.servlet/<artifactId>jdbc
    <version>1.2</version>
</dependency>
    .0.-- <!//https:/mvnrepository.com/<artifactId>jstl/<artifactId>jstl-<artifactId>mysql-mysql -->
jdbc
    java/<groupId>org.springframework
    <groupId>mysql-<artifactId>mysql-connector/<artifactId>jdbc
    <version>8java<11</version>
</dependency>
    .0.-- <!//https:/mvnrepository.com/artifact/spring-org.springframework -->
jdbc
    <dependency>/<groupId>org.springframework
    <groupId>org.springframework-<artifactId>spring/<artifactId>jdbc
    <version>5.1.1.RELEASE</version>
</dependency>

2、Criar classe bean

Aqui, a classe bean contém variáveis correspondentes aos campos existentes no banco de dados (e métodos setter e getter).

Emp.java

package com.w3codebox.beans;  
  
public class Emp {  
private int id;  
private String name;  
private float salary;  
private String designation;  
  
public int getId() {  
    return id;  
}  
public void setId(int id) {  
    this.id = id;  
}  
public String getName() {  
    return name;  
}  
public void setName(String name) {  
    this.name = name;  
}  
public float getSalary() {  
    return salary;  
}  
public void setSalary(float salary) {  
    this.salary = salary;  
}  
public String getDesignation() {  
    return designation;  
}  
public void setDesignation(String designation) {  
    this.designation = designation;  
}  
  
}

3、create controller class

EmpController.java

package com.w3codebox.controllers;   
import java.util.List;  
import org.springframework.beans.factory.annotation.Autowired;  
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;  
import org.springframework.web.bind.annotation.PathVariable;  
import org.springframework.web.bind.annotation.RequestMapping;  
import org.springframework.web.bind.annotation.RequestMethod;   
import com.w3codebox.beans.Emp;  
import com.w3codebox.dao.EmpDao;  
@Controller  
public class EmpController {  
    @Autowired  
    EmpDao dao;//will inject dao from XML file  
      
    /*It displays a form to input data, here "command" is a reserved request attribute 
     *which is used to display object data into form 
     */  
    @RequestMapping("/empform")  
    public String showform(Model m){  
        m.addAttribute("command", new Emp());
        return "empform"; 
    }  
    /*It saves object into database. The @ModelAttribute puts request data 
     *  into model object. You need to mention RequestMethod.POST method  
     *  because default request is GET*/  
    @RequestMapping(value="/save, method = RequestMethod.POST)  
    public String save(@ModelAttribute("emp") Emp emp){  
        dao.save(emp);  
        retornar "redirecionar:/viewemp";//will redirect to viewemp request mapping  
    }  
    /* It provides list of employees in model object */  
    @RequestMapping("/viewemp"  
    public String viewemp(Model m){  
        List<Emp> list = dao.getEmployees();  
        m.addAttribute("list", list);
        return "viewemp";  
    }  
    /* It displays object data into form for the given id.  
     * The @PathVariable puts URL data into variable.*/  
    @RequestMapping(value="/editemp/{id}"  
    public String edit(@PathVariable int id, Model m){  
        Emp emp = dao.getEmpById(id);  
        m.addAttribute("command", emp);
        return "empeditform";  
    }  
    /* It updates model object. */  
    @RequestMapping(value="/editsave, method = RequestMethod.POST)  
    public String editsave(@ModelAttribute("emp") Emp emp){  
        dao.atualizar(emp);  
        retornar "redirecionar:/viewemp";  
    }  
    /* Elimina o registro para o id fornecido na URL e redireciona para /viewemp */  
    @RequestMapping(value="/excluiremp/{id}",método = RequestMethod.GET)  
    public String excluir(@PathVariable int id){  
        dao.excluir(id);  
        retornar "redirecionar:/viewemp";  
    }   
}

4、Criar classe DAO

Vamos criar uma classe DAO para acessar os dados necessários no banco de dados.

EmpDao.java

package com.w3codebox.dao;  
import java.sql.ResultSet;  
import java.sql.SQLException;  
import java.util.List;  
import org.springframework.jdbc.core.BeanPropertyRowMapper;  
import org.springframework.jdbc.core.JdbcTemplate;  
import org.springframework.jdbc.core.RowMapper;  
import com.w3codebox.beans.Emp;  
  
public class EmpDao {  
JdbcTemplate template;  
  
public void definirTemplate(JdbcTemplate template) {  
    this.template = template;  
}  
public int salvar(Emp p){  
    String sql="insert into Emp99(nome,salário,designação) valores('"+p.getNome()+"',"+p.getSalário()+",'"+p.getDesignation()+"')";  
    return template.update(sql);  
}  
public int update(Emp p){  
    String sql="update Emp99 definir nome='"+p.getNome()+",
salário="+p.getSalário()+"designação='"+p.getDesignation()+"' where id="+p.getId()+"";  
    return template.update(sql);  
}  
public int delete(int id){  
    String sql="delete from Emp99 where id="+id+"";  
    return template.update(sql);  
}  
public Emp getEmpById(int id){  
    String sql="select * from Emp99 where id=?";  
    return template.queryForObject(sql, new Object[]{id},new BeanPropertyRowMapper<Emp>(Emp.class));  
}  
public List<Emp> getEmployees(){  
    return template.query("select * from Emp99",new RowMapper<Emp>(){  
        public Emp mapRow(ResultSet rs, int row) throws SQLException {  
            Emp e=new Emp();  
            e.setId(rs.getInt(1));  
            e.setName(rs.getString(2));  
            e.setSalary(rs.getfloat(3));  
            e.setDesignation(rs.getString(4));  
            return e;  
        }  
    });  
}  
}

5oferecendo a entrada do controlador no arquivo web.xml

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>SpringMVC</display-name>
   <servlet  
    <servlet-name>spring</servlet-name>  
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>  
    <load-on-startup>1</load-on-startup>    
</servlet>  
<servlet-mapping>  
    <servlet-name>spring</servlet-name>  
    <url-pattern>/</url-pattern>  
</servlet-mapping>  
</web-app>

6、在xml文件中定义Bean

spring-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<context:component-scan base-package="com.w3codebox.controllers></context:component-scan>  
  
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">  
<property name="prefix" value="/WEB-INF/jsp/></property>  
<property name="suffix" value=".jsp"></property>  
</bean>  
  
<bean id="ds" class="org.springframework.jdbc.datasource.DriverManagerDataSource">  
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>  
<property name="url" value="jdbc:mysql:<//localhost:3306/test"></property>  
<property name="username" value=""></property>  
<property name="password" value=""></property>  
</bean>  
  
<bean id="jt" class="org.springframework.jdbc.core.JdbcTemplate">  
<property name="dataSource" ref="ds"></property>  
</bean>  
  
<bean id="dao" class="com.w3codebox.dao.EmpDao">  
<property name="template" ref="jt"></property>  
</bean>     
</beans>

7、criar páginas de solicitação

index.jsp

<a href="empform">Adicionar Funcionário</a>
<a href="viewemp">Ver Funcionários</a>

8、criar outros componentes de visualização

empform.jsp

<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>  
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>  
        <h1>Adicionar novo Funcionário</h1>
       <form:form method="post" action="save">  
        <table >  
         <tr>  
          Nome : </td> 
          <td><form:input path="name"  /></td>
         </tr>  
         <tr>  
          Salário :</td>  
          <td><form:input path="salary" /></td>
         </tr> 
         <tr>  
          Designação :</td>  
          <td><form:input path="designation" /></td>
         </tr> 
         <tr>  
          td> </td>  
          <td><input type="submit" value="Salvar" /></td>  
         </tr>  
        </table>  
       </form:form>

empeditform.jsp

aqui"/SpringMVCCRUDSimple" é o nome do projeto. Se você usar outro nome de projeto, altere este nome. Para aplicações em tempo real, você pode fornecer o URL completo.

<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>  
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>  
        <h1>Editar Funcionário</h1>
       <form:form method="POST" action="/SpringMVCCRUDSimple/editsave">  
        <table >  
        <tr>
        <td></td>  
         <td><form:hidden  path="id" /></td>
         </tr> 
         <tr>  
          Nome : </td> 
          <td><form:input path="name"  /></td>
         </tr>  
         <tr>  
          Salário :</td>  
          <td><form:input path="salary" /></td>
         </tr> 
         <tr>  
          Designação :</td>  
          <td><form:input path="designation" /></td>
         </tr> 
         
         <tr>  
          td> </td>  
          <td><input type="submit" value="Editar Salvar" /></td>  
         </tr>  
        </table>  
       </form:form>

viewemp.jsp

    <%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>  
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>  
    <h1>Lista de Funcionários</h1>
    <table border="2" width="70%" cellpadding="2">
    <tr><th>Id</th><th>Nome</th><th>Salário</th><th>Designação</th><th>Editar</th><th>Excluir</th></tr>
    <c:forEach var="emp" items="${list}"> 
    <tr>
    ${emp.id}</td>
    ${emp.name}</td>
    ${emp.salary}</td>
    ${emp.designation}</td>
    <td><a href="editemp/${emp.id}>Editar</a></td>
    <td><a href="deleteemp/${emp.id}>Excluir</a></td>
    </tr>
    </c:forEach>
    </table>
    <br/>
    <a href="empform">Adicionar novo Funcionário</a>/a>

Saída:


Clique Adicionar Funcionáriovocê verá a seguinte tabela.


Preencha o formulário e então Clique em Salvarpara adicionar o item ao banco de dados.


Agora, clique EditarPara fazer algumas alterações nos dados fornecidos.


Agora, clique Editar e Salvarpara adicionar o item alterado ao banco de dados.


Agora, clique ExcluirExclua o item do banco de dados.